About Redundancy - Extreme Networks Summit X150 Series Hardware Installation Manual

About Redundancy

When your stack is operational, one switch is the primary (or master) switch that is responsible for
running network protocols and managing the stack. To provide recovery in case of a break in the stack
connections, you can configure redundancy by designating a backup switch to take over as master if the
master switch fails. When you perform the initial software configuration of the stack, the "easy setup"
configuration option automatically configures redundancy, with slot 1 as the master and slot 2 as the
backup. You can also configure additional switches as "master-capable" to become a stack master in
case the initial backup switch fails.
In a stack that combines Summit X460, X480, or X650 series switches with other Summit switch models,
a Summit X460, X480, or X650 series switch might provide more memory and more features than other
Summit switch models in the stack. These differences can affect master node selection, backup node
selection, and failover operation. The master and backup roles should be assigned to switches from the
same series. For example, if the master node is a Summit X480 series switch, the backup node should
also be a Summit X480 switch. Similarly, if the master node is a Summit X650 series switch, the backup
node should also be a Summit X650 switch.
The choice of which switches should be the master and backup switches is based on a combination of
the feature scalability of each switch, along with the switch speed.
qualities for the different switch models and can help you plan the physical placement of the switches
in the stack.
Table 47: Scalability and Speed Comparison for Summit Switch Series
Speed
Higher
X250e
X150
Lower
In a stack that has switch models from more than one Summit series, refer to
guidelines:
If the scalability is the same for all switches in the stack, use models with higher speed as the stack
●
master and backup.
If the speed is the same for all switches in the stack, use models with higher scalability as the stack
●
master and backup.
Always choose the switches with the highest scalability as the stack master and backup, even if those
●
particular switches have lower speed ratings.
For example, in a stack that combines Summit X480 series switches with Summit X650 series switches,
Extreme Networks recommends assigning the master/backup roles to two Summit X480 series switches.
In a stack with multiple master-capable switches, it is possible for more than one switch to try become
the stack master if the stack is physically severed. Such a dual-master condition would cause confusion
and loss of connectivity in your network. To resolve a dual-master condition, you must be able to log in
to each severed stack segment, either over the management network (using the Ethernet management
port on a switch in the segment) or through a direct console port connection to each switch in the
segment.
Stack configuration, easy setup, and redundancy are fully described in the ExtremeXOS Concepts Guide.
Summit Family Switches Hardware Installation Guide
------> Higher
X480
X460 X650
X450a
X450e
X350
Table 47 shows the hierarchy of these
Table 47 and follow these
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